Name: Tsvyatko Dorovski
UNI: td2177

Schneider and Gersting
Chapter 1
Problem 10

John Vincent Atanasoff

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John Vincent Atanasoff
The father of the computer
(October 4, 1903 - June 15, 1995)

John Vincent Atanasoff is known as the father of the computer. With the help of one of his students Clifford E. Berry, in Iowa State College, during the 1940s, he created the ABC (Atanasoff-Berry Computer) that was the first electronic digital computer.

John Vincent Atanasoff was born in Hamilton, New York on 4 of October 1903. His father Ivan Atanasov was born in a country village named Boiajik, in Bulgaria. Ivan Atanasov's parents were killed in 1876 in the Bulgarian war against the Turkish slavery when he was 1 year old. 12 years later in 1889 he immigrated in United States with his uncle. In USA, they arrived in Ellis Island where his last name was changed to Atanasoff. There he married a mathematics schoolteacher Iva Lucena Purdy, who was the mother of John Vincent Atanasoff. Together they had 9 more children.

After John Vincent Atanasoff was born, his father accepted a position as a senior electrical engineer in Osteen, Florida and later they moved in Brewster, Florida. This was the place where John Vincent completed grade school and started to get first understanding of the various electricity concepts. At 9 years he was fixing broken electricity wires in his home, which was the first house with electricity they lived so far.

John Vincent Atanasoff was a very good student. He was also interested in various sports and especially in baseball. Overall, his school years were normal until the day when his father bought a new Dietzgen slide rule for his work. Atanasoff was fascinated by this mathematical tool. He quickly learned how to use it and was really amazed how he was able to get correct results using the rule. Not later after this, he became very interested in the mathematics behind the rule and at 9 years, he started to study trigonometric functions and logarithms. With the help of his mother, he read various mathematic books for collage students. He quickly became familiar with differential equations and other fairly difficult mathematical concepts. His mother introduced the young boy to the number systems based on a different number than 10. This is how he first learned about the base-two number system.

In 1919 the Atanasoff's family moved to a farm in Old Chicora, Florida. This is where he entered into the Mulberry high school. He completed the entire school course, with concentration in science and mathematics, in two years with straight A's. And he already knew that he wanted to study theoretic physics. After this, in 1921 he was accepted in the University of Florida in Gainesville. However, the university didn't offer a specific program in theoretic physics and Atanasoff signed for electrical engineering degree. In 1925 he graduated, again with straight A's, with a Bachelor of Science in electrical engineering. Although, offered a various scholarships from some of the best schools in the country, including Harvard University, the 22 years than old John Vincent Atanasoff, decided to accept the offer from the Iowa State College, which was famous with its engineering and science programs. This was where, later he invented the first digital computer in the world.

During his master's in the university, John had a very busy schedule. He was working towards his degree and in the same time he was teaching two undergraduate courses in mathematics. However, he found time to meet with Lura Meeks, who soon after his graduation became his wife.

In June 1926 John graduated from the Iowa State College with Masters of Science in mathematics. He accepted an offer from the university to teach mathematics. At first, his wife was teaching in a school in Montana, but soon she quit her job and moved back to Ames. So in 1929 their first child was born, a daughter called Elsie. Later, they had 2 more children, a boy and a girl. After Elsie was born, they moved to Madison, Wisconsin where John was taking his doctorate in theoretical physics. During his work on his final thesis, "The Dielectric Constant of Helium" Atanasoff had his first experience with serious computing. He was working with Monroe calculator, which was one of the best calculators at that time, but still it gave him a really hard time and he had to spend hours performing various calculations. It was this experience that made Atanasoff to think strongly in the course of developing a better computing machine. So after he received his Ph.D. in 1930, he accepted an offer from the Iowa State College as an assistant professor in mathematics and physics, and the family moved back to Ames.

In the university, Atanasoff started to make various experiments with vacuum tubes and radio signals as well as various electronic devices and was really determined to develop an advanced computing machine. In the mean time he was promoted to an associate-professor in physics and mathematics.

In the following years Atanasoff continued to examine various mathematical devices and he classified them into two groups: analog and digital devices. The main problem that the inventor found was that the analog devices were slow and their accuracy was dependent upon the performance of all the parts in them.

Around year 1937 John was still obsessed with the computer problem he was trying to solve. As the story in various sources tells including the Iowa State Collage archives:

" the winter months of 1937. One night, frustrated after many discouraging events, he got into his car and started driving without destination. Two hundred miles later, he pulled onto a roadhouse in the state of Illinois. Here, he had a drink of bourbon and continued thinking about the creation of the machine. No longer nervous and tense, he realized that this thoughts were coming together clearly. He began generating ideas on how to build this computer! After receiving a grant of $650 from Iowa State College in March 1939, Atanasoff was ready to embark in this exciting adventure. To help him accomplish his goal, he hired a particularly bright electrical engineering student, Clifford E. Berry. From 1939 until 1941 they worked at developing and improving the ABC, Atanasoff-Berry Computer, as it was later named."

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The ABC computer was the first electronic digital computing device. It was designed with a specific purpose, to solve systems of simultaneous up to 29 linear equations. The machine exact operation was to accept two linear equations at a time with up to 29 variables and a constant, using this data it could eliminate one of the variables. Following this way, the machine could continue by eliminating each time one variable, until the entire system of equations was solved.

Although, as one can see above, the ABC was not a general-purpose computer (its function was fixed), meaning that it did not implemented the stored program architecture (Von Neumann architecture). It still was the first to implement 3 of the most important ideas used in computers now-days. The first and probably most important was using binary digits (1's and 0's) to represent all the numbers in a given data. The second was to perform all the calculations using electronics instead of mechanical switches and wheels. And the third was using the principle from the Von Neumann architecture where the memory and the computations were separate. The ABC also implemented another important idea using a regenerative capacitor memory that is still used now-days in Dynamic Random Access Memory. This means that since the capacitors are loosing their charge pretty quickly they need to be given a new electronic charge every few milliseconds.

The exact specifications and physical characteristics of the ABC as given in were:

"The system weighed more than seven hundred pounds (320 kg). It contained approximately 1 mile (1.6 km) of wire, 280 dual-triode vacuum tubes, 31 thyratrons, and was about the size of a desk.


The memory of the Atanasoff-Berry Computer was a pair of drums, each containing 1600 capacitors that rotated on a common shaft once per second. The capacitors on each drum were organized into 32 "bands" of 50 (30 active bands and 2 spares in case a capacitor failed), giving the machine a speed of 30 additions/subtractions per second. Data was represented as 50-bit binary fixed point numbers. The electronics of the memory and arithmetic units could store and operate on 60 such numbers at a time (3000 bits).

The AC power line frequency of 60 Hz was the primary clock rate for the lowest level operations.

The logic functions were fully electronic, implemented with vacuum tubes. The family of logic gates ranged from inverters to two and three input gates. The input and output levels and operating voltages were compatible between the different gates. Each gate consisted of one inverting vacuum tube amplifier, preceded by a resistor divider input network that defined the logical function.


There were two forms of input and output. Primary user input and output and an intermediate results output and input. The intermediate results storage allowed operation on problems too large to be handled entirely within the electronic memory. (The largest problem that could be solved without the use of the intermediate output and input was two simulataneous equations, a trivial problem.)

Intermediate results were written onto paper sheets by electrostatically modifying the resistance at 1500 locations to represent 30 of the 50 bit numbers (one equation). Each sheet could be written or read in one second. The reliability of the system was limited to about 1 error in 100,000 calculations by these units, primarily attributed to lack of control of the sheets' material characteristics. In retrospect a solution could have been to add a parity bit to each number as written. This problem was not solved by the time Atanasoff left the university for war-related work.

Primary user input was via standard punched cards and output via a front panel display."

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As seen above, although a fascinating for its time invention and huge step for the computers, the ABC was not able solve an entire system of equations automatically. It needed an operator to set up the different functions like addition, subtraction, reading, writing, converting from binary to decimal, etc. Now-days, this is implemented with the use of boot programs.

Here I want to explain exactly why we say that ABC was not a general-purpose computer. The main problem was that its function (its program) was fixed. In other words, it did implement part of the Von Neumann architecture where the processor is separate from the memory, but it didn't implement the stored-program part. Meaning that the memory was used only to be fed with data, the actual program was not in the memory, but it was physically implemented. This is why when we say "stored-program" it means that both the program and the data are in the memory and they both could be changed and we call such a computer a "general purpose computer", meaning that it could be reprogrammed for a different purpose. The ABC could be used only for what it was initially created for (solving a system of linear equations with up to 29 variables). So its data could be changed, but not its function.

It is important to mention that the Atanasoff-Berry Computer was never patented and this is way it was not know until 1960's. Before this, the ENIAC (Electronic Numerical Integrator and Computer) computer was considered as the first computer in modern words. The problem rose because at the end of his project John Atanasoff was called on duty for the Second World War and no one from the university did a patent on the ABC. However, in 1973 a U.S. District Court ruled that the ENIAC principals were taken from the ABC and stated the Atanasoff-Berry Computer as the first computer in the world.

Later for his work on the ABC on November 13, 1990, John Vincent Atanasoff was awarded the National Medal of Technology by the President George H. W. Bush.

The exact conditions around the patent issue are well described in as follows:

" John Atanasoff met John Mauchly at the December 1940 meeting of the American Association for the Advancement of Science in Philadelphia, where Mauchly was demonstrating his "harmonic analyzer". This was an analog calculator for analysis of weather data. Atanasoff told Mauchly about his new digital device and invited him to see it. Also during the Philadelphia trip, Atanasoff and Berry visited the patent office in Washington, where their research assured them that their concepts were new. A January 15, 1941 story in the Des Moines Register announced the ABC as "an electrical computing machine" with more than 300 vacuum tubes that would "compute complicated algebraic equations. In June 1941 Mauchly visited Atanasoff in Ames, Iowa to see the ABC. During his four day visit as Atanasoff's houseguest, Mauchly thoroughly discussed the prototype ABC, examined it, and reviewed Atanasoff's design manuscript in detail. Up to this time Mauchly had not proposed a digital computer. In September 1942 Atanasoff left Iowa State for a wartime assignment as Chief of the Acoustic Division with the Naval Ordnance Laboratory (NOL) in Washington D.C. He entrusted his patent application for the ABC to Iowa State College administrators. It was never filed. Mauchly visited Atanasoff multiple times in Washington during 1943 and discussed Atanasoff's computing theories, but did not mention that he was working on a computer project himself until early 1944. (Mollenhoff, p. 62-66). John Mauchly and J. Presper Eckert's construction of ENIAC, the first general purpose electronic computer, during 1943-1946 was to lead to a legal dispute two decades later over who was the actual inventor of the computer.

By 1945 the Navy, too, had decided to build a large scale computer, on the advice of John von Neumann. Atanasoff was put in charge of the project, and he asked Mauchly to help with job descriptions for the necessary staff. However, Atanasoff was also given the responsibility for designing acoustic systems for monitoring atomic bomb tests. That job was made the priority, and by the time he returned from the testing at Bikini Atoll in July of 1946, the NOL computer project was shut down due to lack of progress, again on the advice of von Neumann.

Mauchly and Eckert applied for a patent on a "General-Purpose Electronic Computer" in 1947, which was finally granted in 1964. The rights to the patent had been sold in 1951 to Remington Rand (to become Sperry Rand); that company started demanding royalty payments from other computer manufacturers in the late 1960's.

The dispute over patent royalties eventually resulted in a lawsuit filed on May 26, 1967 by Honeywell Inc. against Sperry Rand in U.S. District Court in Minneapolis, Minnesota challenging the validity of the ENIAC patent. The trial, one of the longest and most expensive in the federal courts to that time, began on June 1, 1971, lasted until March 13, 1972, had 77 witnesses, plus 80 depositions and 30,000 exhibits. Atanasoff's machine was introduced as prior art. The case was legally resolved on Friday, October 19, 1973, when U.S. District Judge Earl R. Larson held the patent invalid, ruling that the ENIAC derived many basic ideas from the Atanasoff-Berry Computer. Judge Larson explicitly stated, "Eckert and Mauchly did not themselves first invent the automatic electronic digital computer, but instead derived that subject matter from one Dr. John Vincent Atanasoff". The decision in Honeywell Inc. v. Sperry Rand Corp. et al., was so well supported that Sperry declined to appeal. The decision received little publicity at the time, perhaps because it was overshadowed by the Watergate Era "Saturday Night Massacre" firing of special prosecutor Archibald Cox by President Richard Nixon the next day. While legally vindicated, Atanasoff's victory was incomplete as the ENIAC, rather than the ABC, continued to be widely regarded as the first computer until after his death."

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As mentioned above in 1942 John Atanasoff was called on duty and he started a defense related position in the Naval Ordnance Laboratory in Washington, as a theoretical physicists. There, he was working on various projects related to mines disarming, underwater bombs, rockets commanding, etc. Because of the long separation during the Second World War, Atanasoff and his wife were divorced in 1949 and in the same year John married Alice Crosby.

In the period between 1942 and 1966, most of the scientist work was related to the Dynamics of the See Vessels. He holds patents to over 30 different devices some of them like a device for capturing and recording seismic sound waves, a post office sorting system, automated systems for package preparation and others.

After a long sickness Atanasoff died on June 15 1995, in his home in Maryland.

In 1997 a project to develop a fully functional replica of the ABC, with a $350,000 budget, was completed in the Ames Laboratory, located in the Iowa State Collage. Right now, it can be seen on display on the first floor of the lobby of the Durham Center for Computation at Iowa State University. This is also where, most of the archives related to the development of the Atanasoff-Berry Computer, are held. There are many pictures, videos and a lot of information as well as a full documentation of the court trial led to the final decision that indeed it was the ABC - the first computer in the world.

See below a scheme of the Atanasoff-Berry Computer

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See on this site
More pictures of the Atanasoff-Berry Computer and its different parts.